Conventionally, various compounds have been applied as an immunosuppressive agent to immunologic diseases such as rejection after transplant surgery and atopic dermatitis. For example, Cyclosporine A (CysA) and FK 506 are commonly known immunosuppressive agents. However, when administered to animals, these immunosuppressive agents are also known to cause side effects such as loss of renal function, hypertension, decrease of insulin secretion amount and neurotoxicity. Immunosuppressive agents other than CysA and FK 506 have been also been found to cause various side effects and an immunosuppressive agent having fewer side effects is desired.
Currently, besides treatment by the above synthetic compounds, gene therapy, wherein a vector comprising a foreign gene is administered to a human, is attracting attention and studies at a clinical level are being conducted for various diseases. However, the vector used for gene therapy has many problems that need to be solved, such as efficiency of introduction into cells, time required from administration to expression of the protein and side effects when the vector is administered to a human. Also, various peptide preparations have been considered but at present, none are used clinically.
Cardiac hypertrophy refers to the condition of the heart becoming larger than usual due to genetic background or pressure load and may lead to heart failure. However, a cardiac hypertrophy suppressive agent that prevents progression of or promotes involution of cardiac hypertrophy is not commercially available at present. This is because the currently known cardiac hypertrophy suppressive agent has strong side effects and therefore cannot actually be applied to a human. Consequently, medication that prevents or remedies cardiac hypertrophy and does not have problems such as side effects is strongly desired.